1. Field of the Invention
The present invention relates to a numerical controller, and more particularly, to a numerical controller capable of detecting noise, power flicker, an impact and the like which become factors of malfunction of a device, and capable of narrowing down causes of the factors.
2. Description of the Related Art
FIGS. 12 and 13 are diagrams for describing detection data of a machine tool which is controlled by a conventional numerical controller. As shown in FIG. 12, the machine tool 10 is composed of: a numerical controller 20; an amplifier 30, a motor 40 and an I/O unit 50 which are controlled by the numerical controller 20; a table and a tool rest 60 driven by the motor, and a peripheral device 70 operated by a signal from the I/O unit.
As shown in FIG. 13, when the machine tool 10 operates, the numerical controller 20 processes a ladder program and sends a control signal to the I/O unit 50. The I/O unit 50 receives the control signal and operates, sends an I/O signal to the connected peripheral device 70, and operates the peripheral device 70. The peripheral device 70 has an inductive load such as a relay and a solenoid valve as well as a capacitive load such as a lamp, but these operations become factors which cause noise and power flicker. The noise and the power flicker become factors which cause intermittent malfunction of the numerical controller 20.
The numerical controller 20 processes a processing program, and sends a control signal to the amplifier 30. The amplifier 30 receives the control signal and drives the motor 40, and the table and the tool rest 60 mounted on the motor 40 operate. If the table and the tool rest 60 operate with abrupt acceleration or deceleration, an impact generates. A strong impact and an intermittent impact continuing for a long time become factors which damage parts of the numerical controller 20.
As countermeasure against noise, power flicker, an impact and the like, JP 2003-308107 A discloses a device incorporating a detecting unit therein and capable of specifying a generation state, generation time and magnitude of a factor which causes malfunction of a device.
According to this conventional technique, it is possible to detect a generation state, generation time and magnitude of a factor which causes malfunction of a device. However, to take countermeasure against a cause of the factor, it is necessary to individually operate a table, a tool rest and a peripheral device while checking information from the detecting unit, and to check the noise, power flicker and an impact, and deserved effort and time are required to specify a cause of a factor which causes malfunction.
Further, operation of a peripheral device controlled by a ladder program of the numerical controller, and operations of a table and a tool rest controlled by a processing program are related to noise, power flicker, an impact and the like generated due to operation in a machine tool, but in operation of an actual machine, operations of the table and the tool rest are different from each other due to the processing program, and a plurality of motors operate at the same time in some cases. A plurality of peripheral devices are simultaneously operated by the processing of the ladder program which controls input and output in some cases, but it is difficult to replicate such motion when a factor is specified and researched.